Titanium-aluminum-silver alloys



U t d ms. Parent 2,810,642 TITANIUM-ALUMINUM-SILYER ALLOYS Robert I.Jaltee, Worthington, and Horace R. Ogden, (Columbus, Ohio, asslgnors,bynaesne assignments, to Rem-Cru Titanium, ]nc., Midland, Pin, acorporation of Pennsylvania No Drawing. Application January 15, 1953,Serial No. 331,504

9 Claims. (Cl. 7 -1755) This invention pertains to ductile titanium-basealloys containing aluminum and silver as essential constituents. Broadand preferred ranges for the aluminum and 2,810,642 Patented Oct. 22,1957 ice an ultimate strength at least ten percent in excess of that ofthe unalloyed titanium base metal, consistent with retention of goodductility. For the broad range oi analysis the minimum bend ductilitiesdo not exceed T or possess tensile elongations under about 2%. For thepreferred range of analysis the minimum bend ductilities do not exceedabout 7 T, with elongation ranging up wards of about 10%.

Owing to their substantially all-alpha microstructure the alloys may bewelded without appreciable impairment of ductility in the welded ascompared to the non-welded portions.

The following Table 1 gives mechanical properties of typical alloysaccording to the invention, as produced from titanium base metal ofcommercial purity. In the table VHN designates Vickers hardness, whileMBR signifies Minimum bend radius.

Table I MECHANICAL PROPERTIES OF Tl-Al-Ag ALLOYS [These alloys were 980C. torgeg, 850 0. rolled to 0.040 inch, and annealed two hours at 8 0 C.and rapidly cooledJ silver contents consistent with retention ofadequate ductility for fabrication purposes are as tollows:

Range. Percent Broad Preferred The alloys of the invention may bematerially strengthened without undue loss of ductility by controlledadditions of the interstitials carbon, oxygen and nitrogen in amountsranging up to about 0.2% each, the aggregate content not to exceed about0.6%.

These alloys may be made by melt-casting in a cold mold, employing anelectric arc in an inert atmosphere, or may be produced in other ways inwhich the alloy is rendered molten before casting.

The titanium base metal employed may be the product of high purityobtained by the iodide" process debe the product of commercial purityproduced by the scribed in U. S. Patent 1,671,213 to Van Arkel; or maymagnesium reduction of titanium tetrachloride by the process describedin U. S. Patent 2,205,854 to Kroll; or by other procedures producingtitanium metal of equivalent purity.

The alloys of the invention possess a substantially allalphamicrostructure at room temperature. This results from the alphamicrostruclure of the titanium at room temperature, and the fact thataluminum together with the interstitials carbon, oxygen and nitrogen areall alpha promoters or stabilizers, while silver has so little efiect onthe beta transus temperature of titanium that its effect is practicallyneutral. Although formerly considered an alpha stabilizer it now appearsmore properly grouped as a borderline beta stabilizer.

These alloys are further characterized in possessing The following Table11 gives test data on the weldability of the alloys of Table I as arewelded in an inert atmosphere, viz. argon.

Table II MBR, T

Composition, Percent (Balance Titanium) Welded Not Welded It will b seenfrom the above data that the ductility of these alloys is substantiallyunaffected by welding.

We claim:

1. A titanium base alloy consisting essentially of about: 0.5 to 8%aluminum, 0.5 to 15% silver, and up to 0.2% each of carbon, oxygen andnitrogen, characterized in having an ultimate strength at least tenpercent in excess of the unalloyed titanium base metal, and a minimumbend radius of not over 20 T.

2. A titanium base alloy consisting essentially of about: 1 to 7.5%aluminum, 1 to 10% silver, and up to 0.2% each of carbon, oxygen andnitrogen, characterized in having an ultimate strength at least tenpercent in excess of the unalloyed titanium base metal, and a minimumbend ductility of not over 7 T.

3. An alloy consisting essentially of about: 0.5 to 8% aluminum, 0.5 to15% silver, up to 0.2% each of carbon, oxygen and nitrogen, balancetitanium, characterized in having an ultimate strength at least tenpercent in excess of the unalloyed titanium base metal, and a minimumbend radius of not over 20 T.

4. An alloy consisting essentially of about: 1 to 7.5%

aluminum, about 1 to 10% silver, up to 0.2% each of carbon, oxygen andnitrogen, balance titanium, characterized in having an ultimate strengthat least ten percent in excess of the unalloyed titanium base metal, anda minimum bend ductility of not over 7 T.

5. An alloy consisting of about: 0.5 to 8% aluminum, 0.5 to 15% silver,up to 0.2% each of carbon, oxygen and nitrogen, balance titanium,characterized in having an ultimate strength at least ten percent inexcess of the unalloyed titanium base metal, and a minimum bend radiusof not over 20 T.

6. An alloy consisting of about: 1 to 7.5% aluminum, about 1 to 10%silver, up to 0.2% each of carbon, oxygen 4 and nitrogen, balancetitanium, characterized in having an ultimate strength at least tenpercent in excess of the unalloyed titanium base metal, and a minimumbend ductility of not over 7 T.

7. An alloy consisting of 1-4% aluminum, 2-8% silver, balance titanium.

8. An alloy consisting of l-6% aluminum, 28% silver, balance titanium.

9. An alloy consisting of about: 0.5 to 8% aluminum, 0.5 to 15% silver,up to 0.2% each of carbon, oxygen and nitrogen, and the balancetitanium.

No references cited.

1. A TITANIUM BASE ALLOY CONSISTING ESSENTIALLY OF ABOUT:0.5 TO 8%ALUMINUM, 0.5 TO 15% SILVER, AND UP TO 0.2% EACH OF CARBON, OXYGEN ANDNITROGEN, CHARACTERIZED IN HAVING AN ULTIMATE STRENGTH AT LEAST TENPERCENT IN EXCESS OF THE UNALLOYED TITANIUM BASE METAL, AND A MINIMUMBEND RADIUS OF NOT OVER 20 T.